Method and system for monitoring building structures

ABSTRACT

Methods and systems are disclosed for monitoring properties of building structures (e.g., monitoring the strength and humidity of concrete structures) using sensor devices embedded in the building structures. The sensor devices collect sensor data and wirelessly transmit the data to portable computer devices operated by users.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 62/263,961 filed on Dec. 7, 2015 entitled METHOD ANDSYSTEM FOR MONITORING THE STRENGTH AND HUMIDITY OF CONCRETE STRUCTURESand U.S. Provisional Patent Application No. 62/371,559 filed on Aug. 5,2016 entitled METHOD AND SYSTEM FOR MONITORING BUILDING STRUCTURES, bothof which are hereby incorporated by reference.

BACKGROUND

The present application relates generally to methods and systems formonitoring properties of building structures, e.g., monitoring thestrength and humidity of concrete slabs and other concrete structures.

BRIEF SUMMARY OF THE DISCLOSURE

In accordance with one or more embodiments, a sensor device is disclosedfor monitoring properties of a building material within which the sensordevice can be embedded. The sensor device is packaged in a removablelight blocking packaging. The sensor device includes a controller,memory associated with the controller, one or more sensors connected tothe controller for measuring one or more properties of the buildingmaterial, an optical sensor connected to the controller for detectingthe presence of light, a power supply for powering components of thesensor device, and a communication module connected to the controller.The controller is configured to receive a signal from the optical sensorwhen light is detected after the sensor device is removed from the lightblocking packaging, and to responsively activate the sensor device. Thecontroller is also configured to receive data on the one or moreproperties of the building material from the one or more sensors afterthe sensor device is removed from the light blocking packaging andembedded in the building material, and to wirelessly transmit data onthe one or more properties of the building material to an electronicdevice external to the building material through the communicationmodule.

In accordance with one or more further embodiments, a portable computerdevice is disclosed. The computer device includes at least oneprocessor, memory associated with the at least one processor, a display,a communication module connected to the at least one processor forreceiving data wirelessly from remote devices, and a program supportedin the memory for monitoring properties of a building structure. Theprogram having a plurality of instructions stored therein which, whenexecuted by the at least one processor, cause the at least one processorto: (a) receive data via the communication module from a plurality ofsensor devices embedded in the building structure, (b) calculate aplurality of metrics relating to the building structure based on thedata received in (a), (c) record locations on a floorplan where each ofthe plurality of sensor devices is positioned, and (d) synchronizeinformation relating to said sensor devices or the building structurewith portable computer devices operated by other users.

In accordance with one or more further embodiments, a sensor device isdisclosed for monitoring properties of a building material within whichthe sensor device can be embedded. The sensor device includes a housing,a controller in the housing, memory in the housing associated with thecontroller, a power supply in the housing for powering components of thesensor device, a communication module in the housing connected to thecontroller, and one or more sensors for measuring one or more propertiesof the building material. The one or more sensors are outside thehousing and connected to the controller by an electrical cable. Thecontroller is configured to receive data on the one or more propertiesof the building material from the one or more sensors and to wirelesslytransmit data on the one or more properties of the building material toan electronic device external to the building material through thecommunication module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exemplary concrete sensor device embedded in aconcrete structure for monitoring the strength and humidity of thestructure in accordance with one or more embodiments.

FIG. 1B illustrates wireless communication between the sensor device inaccordance with one or more embodiments and a smartphone.

FIG. 1C is a screenshot illustrating exemplary strength calculations andtemperature and humidity data displayed to a user in accordance with oneor more embodiments.

FIGS. 1D and 1E are screenshots illustrating sensor device informationdisplayed to a user in accordance with one or more embodiments.

FIG. 2 is a schematic block diagram illustrating select components of aconcrete sensor device in accordance with one or more embodiments.

FIGS. 3A-3C illustrate an exemplary sensor device including anovermolded body in accordance with one or more embodiments.

FIG. 4 is a flow chart illustrating an exemplary sensor deviceovermolding process in accordance with one or more embodiments.

FIG. 5 is a perspective view of a portion schematically illustrating anexemplary printed circuit board (PCB) on which sensing components residein accordance with one or more embodiments.

FIG. 6 is a cross-section view schematically illustrating an exemplaryovermolded sensor device in accordance with one or more embodiments.

FIG. 7 is a cross-section view schematically illustrating an exemplaryovermolded sensor device including a filter supporting structure inaccordance with one or more embodiments.

FIG. 8 is a perspective view of an exemplary filter supporting structurein a sensor device body in accordance with one or more embodiments.

FIG. 9 is a perspective view of an exemplary sensor device having asensing portion separated from a wireless communication portion inaccordance with one or more embodiments.

FIGS. 10A and 10B are top and side views, respectively, of the sensingportion of the sensor device of FIG. 9 in accordance with one or moreembodiments.

FIGS. 11 and 12 are top views of sensing portions including a cable tieand cable tie opening in accordance with one or more embodiments.

FIG. 13 is a top view of a sensing portion, in which the cable tie issubstantially parallel to the electrical cable in accordance with one ormore embodiments.

FIG. 14 is a perspective view of a sensor device including a wirelesscommunication portion and a sensing portion embedded in a buildingstructure in accordance with one or more embodiments.

FIG. 15 is a top view illustrating a sensor device including aretractable electrical cable mechanism in accordance with one or moreembodiments.

FIG. 16 is a perspective view of the sensor device of FIG. 15 embeddedin a building structure in accordance with one or more embodiments.

FIG. 17 is a flowchart illustrating an exemplary process for adding asensor device to a set of sensor devices used at a given site or area inaccordance with one or more embodiments.

FIG. 18 illustrates an exemplary format for a Bluetooth advertisementpacket periodically broadcast by a sensor device in accordance with oneor more embodiments.

FIG. 19 is a flow diagram illustrating an exemplary process forretrieving data by a smartphone app from a sensor device in accordancewith one or more embodiments.

FIG. 20 is a flow diagram illustrating further details of the processfor retrieving data by a smartphone app from a sensor device inaccordance with one or more embodiments.

FIG. 21 illustrates an exemplary data packet received at the smartphoneapp from a sensor device in accordance with one or more embodiments.

FIG. 22 illustrates an exemplary data packet received at the smartphoneapp from a sensor device in accordance with one or more embodiments.

FIG. 23 is a flow chart illustrating an exemplary parsing process by thesmartphone app of data received from a sensor device in accordance withone or more embodiments.

FIG. 24 is a flow chart illustrating an exemplary process of activatinga sensor device in accordance with one or more embodiments.

Like or identical reference numbers are used to identify common orsimilar elements.

DETAILED DESCRIPTION

Various embodiments disclosed herein are directed to methods and systemsfor monitoring one or more properties of building materials, includingbut not limited to concrete and epoxy. In some embodiments, the methodsand systems are used for monitoring one or more properties of an ambientenvironment (e.g., gas ambient such as air, liquid ambient). In someembodiments, properties being monitored include, but are not limited to,the strength and/or relative humidity (RH) of a building structure suchas a concrete structure. The properties are monitored using one or moresensor devices embedded in the structure, which collect and send sensordata wirelessly to smartphones or other computer devices operated byusers outside the building structure. Various other building materialproperties may also be sensed including, but not limited to,temperature, vibration, pH, gas and particle presence, load, andacoustic properties.

In accordance with one or more embodiments, the sensor system generallyincludes two components: a smartphone (or other computer) app and ahardware sensor device. The smartphone app connects to the sensor deviceusing the Bluetooth or Bluetooth Low Energy (BLE) protocol or otherwireless communications protocols such as, e.g., ANT, IEEE 802.11 andWiFi, RFID, NFC, Thread, LoRa, and ZigBee. The sensor device is acombination sensing device and datalogger, with a battery that lasts fora given period of time, which can vary based on intended use. By way ofexample, in some jobs, the battery should last for 28 days, and in otherjobs it should last for two years or more.

FIG. 1A illustrates an exemplary concrete sensor device 10 embedded in aconcrete structure 12 for monitoring the strength and humidity of thestructure. The concrete sensor device 10 is attached to rebar 14 in thestructure using a cable tie 16 (also referred to as a zip tie) or otherattachment mechanism. In addition to rebar 14, the sensor device 10 canalso be attached to other structures within the building materialincluding, but not limited to metal mesh, pipes, or conduits.

FIG. 1B illustrates wireless communication between the sensor device 10and a smartphone 18.

In accordance with one or more embodiments, the smartphone app uses thesmartphone's camera to allow the user to scan a code shown on the sensordevice 10, e.g., a QR code. Accordingly, no extra hardware such as areader is needed to use the system. Once scanned, the app searches for asensor device 10 broadcasting a matching identifier. When found, the appwill then periodically poll the sensor device 10 for updated data.

The smartphone app calculates various metrics based on sensor data,including the strength of concrete (using, e.g., the methods describedin ASTM C-1074). The app interprets the data received from sensordevices using actual mix designs while additionally providing a log ofraw data content to users. The system utilizes a library of data onconcrete mix designs in lieu of general predictions or users needing totest concrete themselves. FIG. 1C is an exemplary screenshotillustrating strength calculations and temperature and humidity datadisplayed to a user on the smartphone in graphs. In accordance with oneor more embodiments, users can share or view the graphs and displayedmetrics with other devices.

In accordance with one or more embodiments, the smartphone app transmitsdata received from the sensor devices to a remote computer system in thecloud, which generates graphs based on the data, and transmits thegraphs to the smartphone to be displayed on the smartphone or sharedwith other devices.

The app can also save floor plan information, e.g., with a “pin drop”feature that allows users to set where on a floor plan a sensor device10 is placed.

The app can also synchronize sensor data, floor plan data, and otherdata with other team members.

Sensor devices are categorized by project and subcategorized by floor.Projects can be described by a project name and project address. Floorsare described by a floor name, concrete mix design and summarystatistics of the sensor devices on that floor. FIGS. 1D and 1E areexemplary screenshots displayed on a user's smartphone 18 illustratingsuch sensor information.

FIG. 2 is a schematic block diagram illustrating select components of aconcrete sensor device 10 in accordance with one or more embodiments.The sensor device 10 includes a printed circuit board (PCB) assemblywith an attached battery. The PCB assembly includes a microcontrollerunit 20, which receives temperature and humidity data from a temperaturesensor 22 and a humidity sensor 24. The microcontroller unit 20 alsoreceives data from an optical sensor 26. The device is powered by thebattery 28 through a power regulator 30. The device communicates withthe smartphone app through a radio 32. Data is stored in a non-volatilememory 34.

In accordance with one or more embodiments, the sensor device 10 isstored in a light-blocking packaging that is removed by the installerprior to installation. When the sensor device 10 is inside a package, itretrieves an optical sensor reading every few seconds. If twoconsecutive readings indicate the sensor 26 is in light, it transitionsto the “waiting for pour” state. In this manner, the sensor activationis not dependent on the installer providing an activation signal (e.g.,flipping a mechanical switch, providing a wireless signal via an app,etc.), and hence eliminates potential user error caused by a userforgetting to activate the sensor device 10 upon installation.

Various other sensor device activation techniques are also possible. Forexample, the sensor device may include a removable streamer or tag that,when removed by the installer, activates the sensor device. Also, thesensor device may include a thin filament in the zip-tie hole that isbroken when a zip-tie is inserted in the hole. Breakage of the filamentis detected and responsively actives the sensor device. As anotherexample, the sensor device may include a pH sensor, which can determinea highly alkaline environment, indicating presence of concrete, and inresponse active the sensor device. As yet another example, the sensordevice may include an NFC reader, allowing a smartphone to turn on thesensor device. In this case, the smartphone broadcasts an NFC signal,and the NFC reader on the sensor device listens for it to activate thedevice.

FIGS. 3A-3C are illustrations of an exemplary sensor device 10 includingan overmolded body 11, according to some embodiments. FIG. 3A is aperspective view of the sensor device 10 including the overmolded body,FIG. 3B is a front view of the sensor device 10 including the overmoldedbody, and FIG. 3C is a back view of the sensor device 10 including theovermolded body. The overmolded body is formed around a PCB thatcomprises the components forming the sensor device 10. The overmoldedbody may be formed of plastic and/or rubber.

As shown in FIG. 3B, the front side of the sensor device 10 includes alight guide 40 located over the optical sensor 26 within the body so asto enable light to pass through to the optical sensor 26 on the PCB. Thesensor device 10 can also include a clear or semi-clear portion (e.g., atransparent plastic faceplate) that allows light to pass through to theoptical sensor 26.

A cable tie 16 and cable tie opening 42 is provided so as to enable easyattachment of the sensor device 10 to construction structures, such asrebar 14 within concrete slabs. Additionally, or alternatively, one ormore attachment openings 44 enable the attachment of the sensor device10 to construction structures using any suitable attachment methods,such as metal wires, cable ties, and/or the like.

As shown in FIG. 3C, the back side of the sensor device body (which may,e.g., be a plastic body) includes a sensor opening 46, which enablessensing components inside the device to sense one or more properties ofthe building materials (e.g., temperature and/or humidity). In otherembodiments the sensor opening may be provided on the front side of thesensor device 10. A membrane filter 48 may be disposed in registry withthe sensor opening (e.g., within the sensor opening, under the sensoropening, over the sensor opening). The membrane filter 48 allows moistvapor (e.g., moist air) into the body (where it can be sensed via therelative humidity sensor mounted on the PCB), while inhibiting orpreventing liquid water, chemicals, debris, etc. from entering. In someembodiments, the membrane is a polytetrafluoroethylene (PTFE) membrane,such as an extruded PTFE (ePTFE) membrane. In some embodiments, nomembrane is used when the sensor being used requires physical contactthe building material being sensed (e.g., a pH sensor).

FIG. 4 is a flow chart illustrating an exemplary sensor deviceovermolding method, according to some embodiments. The method includes,at step 60, forming a PCB, including forming electrical trace lines on asupporting board (e.g., metal lines, such as copper-based metal lines).The PCB may be a single layer and/or multi-layer board, and may includetraces on a front side and/or a backside.

The method also includes assembling a plurality of components on the PCBat step 62. The components include one or more of the components shownin the schematic of FIG. 2, such as sensing components (e.g.,temperature and/or humidity sensors 22, 24), optical sensor 26,microcontroller unit 20, radio, memory, power regulator, battery,resistors, capacitors, and/or inductors.

The method also includes mounting the membrane filter 48 over thesensing components at step 64. In some embodiments, an associated filtersupporting structure is disposed over the membrane filter 48, such thatthe membrane filter 48 is disposed between the sensing components andthe supporting structure. The filter supporting structure holds themembrane filter 48 securely in place over the sensing components.

The filter supporting structure may be a plastic structure formed viaany suitable means, including, but not limited to, injection molding.The filter supporting structure includes an opening through which themembrane makes contact with the external environment (e.g., the buildingmaterial), as shown in the perspective view of an exemplary filtersupporting structure in FIG. 8.

In some embodiments, the filter supporting structure is secured to thePCB using, e.g., an epoxy or a silicone applied to one or more portionsor all of the filter supporting structure in contact with the PCB.

The method further includes overmolding a body (e.g., a plastic and/orrubber body) around at least a portion or all of the PCB at step 66. Theovermolding may be performed utilizing, e.g., a low pressure moldingprocess. The overmolding process is performed so as to ensure that theopening of the filter supporting structure is not covered with moldingmaterial. The overmolded body for the sensor device 10 provides seamlessencapsulation of the PCB and associated components of the sensor, whichensures that during use the building material in which the sensor isplaced does not enter the sensor and damage the components or interferewith the operation of the sensor.

FIG. 5 is a perspective view of a portion of an exemplary PCB 70 onwhich the sensing component(s) (e.g., temperature and/or humiditysensing components 22, 24) reside, according to one embodiment. Itshould be appreciated that the other components may be placed on one orboth sides of the PCB, which is not illustrated in FIG. 5. The sensingcomponent(s) 22, 24 may be one or more packaged components including oneor more semiconductor chips and including a plurality of metal leads 76that upon mounting on the PCB enable electrical connections to metaltraces on the PCB. The sensing component(s) 22, 24 backside may beplaced in contact with a thermal pad on the PCB, which may beelectrically connected to a ground plane of the PCB (e.g., a copperground layer). The metal traces 78 electrically connected to the sensingcomponent(s) may include a power line, a data line, a clock line, and aground line.

FIG. 6 is a cross-section view of an exemplary overmolded sensor device10, according to some embodiments. As illustrated, in some embodiments,the membrane filter 48 is in contact with at least a portion of thesensing component(s). In some embodiments, at least a portion of the topface of the sensing component(s) is disposed in contact with themembrane filter 48. Such a configuration ensures that equilibrium withthe external environment is attained quickly, which has been found to beespecially important for relative humidity sensing. In contrast, thepresence of a substantial gap between the sensing component and themembrane filter 48 may introduce an additional delay (e.g., more thanone day) in attaining sensing equilibrium with the external environment.

In some embodiments, a gap of less than the thickness of the membrane isprovided between the membrane backside and the top face of the sensingcomponent. For example, the membrane filter 48 may have a thicknessbetween about 0.75 mm and about 1.25 mm, and the gap thickness may beless than about 0.5 mm. In some embodiments, a gap of less than abouthalf the thickness of the membrane filter 48 is provided between themembrane backside and the top face of the sensing component.

In some embodiments, the membrane filter 48 is held in contact with thesensing component(s) at least partially with a filter supportingstructure. In other embodiments, the membrane filter 48 is held incontact with the sensing component without any associated supportingstructure (as shown in the cross-section illustration of FIG. 6). Toachieve such a configuration, the membrane filter 48 may be attacheddirectly to the PCB and/or the sensing component(s), for example,utilizing an attachment material disposed around the perimeter of themembrane filter 48 and in contact with the PCB and/or sensingcomponent(s).

FIG. 7 is a cross-section view schematically illustrating an exemplarysensor device including a filter supporting structure 80, according tosome embodiments. The body of the sensor device may be an overmoldedbody 11 formed around a filter supporting structure 80 and leaving anopening to expose the membrane filter 48. Alternatively, the body may beformed from the attachment of injection molded housing portions that areadhered to each other and/or the filter supporting structure. Adherencemay be achieved using epoxy, heat staking, ultrasonic welding, or othersuitable adherence methods.

The filter supporting structure includes one or more shelf regions 84that are in contact with the membrane filter 48 and hold the membranefilter 48 firmly in place over the sensing component(s) 22, 24. Thefilter supporting structure includes one or more legs 86 that areinserted into corresponding holes in the PCB and ensure proper place ofthe filter supporting structure over the sensing component(s). Thefilter supporting structure may be attached to the PCB using anysuitable attachment material, for example, using an epoxy or a silicone.For example, an attachment material, such as epoxy or silicone may bedisposed on the legs and/or base perimeter of the filter supportingstructure. Such an assembly ensures that the membrane filter 48 is in acompressive state, and hence is firmly held in place.

FIG. 8 is a perspective view of an exemplary filter supportingstructure, according to some embodiments. The filter supportingstructure includes a shelf region around an opening 90, which holds themembrane filter 48 firmly in place. In some embodiments, the filtersupporting structure includes a flange portion 92 over the shelfregion(s). The flange configuration is useful for adhering the filtersupporting structure to an injection molded housing, for instance, usingepoxy, heat staking, ultrasonic welding, or other suitable adherencemethods.

FIG. 9 is a perspective view of an exemplary sensor device 100 having aseparate sensing portion 102 electrically connected to a wirelesscommunication portion 104, according to some embodiments. The sensingportion includes the sensing component(s) mounted on a PCB board, asdescribed for FIGS. 5-7. The wireless communication portion includes atleast one wireless communication component (e.g., radio component). Insome embodiments, the wireless communication portion also includes anoptical sensor 26, a microcontroller unit 20, a memory, a powerregulator, and a power source (e.g., a battery).

In some embodiments, the sensing portion includes a humidity sensor. Aspreviously described, a membrane filter 48 is placed over the sensor. Insome embodiments, the sensing portion includes one or more sensingcomponents that sense a plurality of properties. In some embodiments,the sensing portion includes one or more sensing components that senserelative humidity and temperature.

The separate sensing portion is connected to the wireless communicationportion via an electrical cable 106, and enables the placement of thesensing portion deep (e.g., more than about 2 feet, more than about 6feet, or more than about 8 feet from the nearest surface of the buildingmaterial structure) within a building material structure (e.g., a thickconcrete slab) while the wireless communication portion is placed closerto the surface of the building material structure (e.g., less than about1 foot, less than about 8 inches, or less than about 6 inches from thenearest surface of the building material structure). Such aconfiguration enables effective transmission of a wireless communicationsignal out of the building material structure (e.g., a thick concreteslab), while sensing properties from portions deep within the centerregion of the building material structure.

The electrical cable may include a power line, a data line, a clockline, and/or a ground line that are electrically connected to thesensing component(s) in the sensing body, which provides power andsignals to operate the sensing component(s) and to send sensed data fromthe sensing portion to the wireless communication portion. In someembodiments, the electrical cable has a length greater than about 2 feet(e.g., about 3 feet). In some embodiments, the electrical cable has alength greater than about 6 feet (e.g., about 8 feet).

In some embodiments, at least one of the wireless communication portionand the sensing portion includes an overmolded body, as may be formedusing methods similar to that described for FIG. 4. In some embodiments,the wireless communication portion includes an overmolded body. In someembodiments, the sensing portion includes an overmolded body. In someembodiments, the wireless communication portion and the sensing portioninclude overmolded bodies.

FIGS. 10A and 10B are top and side view illustrations, respectively, ofthe sensing portion, according to some embodiments. The sensing portionincludes a sensor opening 104, which may be formed in a manner similarto the sensor opening described in FIGS. 6-8, and may include a membranefilter 48 and/or a filter supporting structure. The sensing portionincludes an attachment opening 107 that enables the attachment of thesensor device 100 to construction structures using any suitableattachment methods, such as metal wires, cable ties, and/or the like.

FIGS. 11 and 12 are top view illustrations of sensing portions includinga cable tie 120 and cable tie opening 122, according to someembodiments. In some embodiments, the cable tie is substantiallyperpendicular to the electrical cable, as illustrated in these drawings.

FIG. 13 is a top view illustration of a sensing portion including acable tie and cable tie opening, according to some embodiments. In someembodiments, the cable tie is substantially parallel to the electricalcable, as illustrated in the drawings.

FIG. 14 is a perspective illustration of a sensor device including awireless communication portion and a sensing portion in use within abuilding structure 130 (e.g., a concrete slab with rebar frame),according to some embodiments. As illustrated, and previously described,the sensing portion may be attached to rebar 14 deep within the concreteslab, whereas the wireless communication portion may be attached torebar 14 closer to a surface 132 of the concrete slab, thereby enablingeffective wireless communication with an external device (e.g., asmartphone 18).

FIG. 15 is a top view illustration of a sensor device including aretractable electrical cable mechanism 140, according to someembodiments. In some embodiments, the retractable electrical cablemechanism includes a spring loaded assembly (or any other suitableretraction mechanism) that retracts the electrical cable. Using such amechanism, a long electrical cable (e.g., greater than about 6 feet) maybe easily manipulated without the need for an installer to handle spareportions of the electrical cable. Furthermore, when only a shorterportion of electrical cable is needed, the installer need not bothersecuring spare portions of the electrical cable as shown in FIG. 14 at134.

FIG. 16 is a perspective illustration of a sensor device including awireless communication portion, a sensing portion, and a retractableelectrical cable mechanism in use within a building structure (e.g., aconcrete slab with rebar frame), according to some embodiments.

In accordance with one or more embodiments, each sensor device includesmultiple sensing portions 102, each being connected to a single wirelesscommunication portion 104 by a separate electrical cable. Each sensingportion can be embedded at a different location in the buildingstructure.

In accordance with one or more embodiments, each sensor device 10includes a power amplifier system to improve communication withsmartphones. The power amplifier system can include a power andlow-noise-amplifier “frontend” system to both boost the output powerwhile also boosting the receiver gain so the device is more sensitive toincoming signals to the device.

In accordance with one or more embodiments, the sensor device 10 alsoincludes a power saving feature to reduce power usage by the amplifiersystem and thereby increase battery life. In accordance with one or moreembodiments, the sensor device 10 uses certain heuristics to determinewhen to turn on the power amplifier system. For instance, the sensordevice can broadcast some of the time using the power amplifier and someof the time without it. The device records whether incoming connectionsfrom a smartphone occurred with the amplifier on or off. If connectionsoccur with the amplifier off, use of the amplifier is discontinued.Otherwise, the amplifier is used for subsequent communications.

In accordance with one or more further embodiments, the power amplifierenables an M2M network, where a sensor device can be connected to eitheranother sensor device (e.g., in a mesh network) or to a relay tosubsequently transmit the data up to the cloud. In this implementation,the smartphone retrieves sensor data from the cloud.

In accordance with one or more further embodiments, the power amplifierenables an M2M network, where a sensor device can be connected toanother sensor device (e.g., in a mesh network), and the sensor devicescooperate to wirelessly communicate sensor directly to a smartphone.

Sensor Firmware

The following describes the general functionality of an exemplary sensorin accordance with one or more embodiments and its interaction with asmartphone app (also referred to herein as the “client”).

Assembly Process

When the sensors are first assembled, a simple quality control programis programmed onto the PCBs that runs various diagnostic procedures toensure the sensor is assembled properly. If this program detects afailure, it flashes an LED in a specific pattern to indicate to thetechnician what failure was detected. If, however, no problems aredetected, the LED is held in a steady state for 2 seconds beforeshutting off and going into lowpower “off” mode. Because the battery forthe sensor is permanently attached to the sensor at this point, thequality control program should be conservative with power usage.

As part of the QC program procedure, the non-volatile memory in thesensor is initialized with default state information that is later usedby the sensor firmware. The state is written as “ASSEMBLY”.

Later, when the sensor firmware has been programmed onto the sensor, itdetects if the non-volatile memory state has been initialized and is inASSEMBLY mode. If so, the sensor shuts down for period of time so atechnician can complete the packaging process. After this interval, thesensor starts up and assumes it is inside a package.

When the sensor is inside a package, it retrieves an optical sensorreading every few seconds. If two consecutive readings indicate thesensor is in light, it transitions to the “waiting for pour” state.

When the sensor is installed while waiting for a pour, it sends a BLEadvertisement about every 2 seconds. The sensor collects a temperaturereading every 30 minutes for the first 60 days and RH reading every 24hours. The sensor retrieves an optical sensor reading every 5 minutes.If consecutive readings over 18 hours indicate the sensor is indarkness, it transitions to the “encased” state. Otherwise, the sensorresets collected sample data, increment the light resets counter by 1,and continues monitoring optical data.

When the sensor is embedded within concrete, it sends a BLEadvertisement about every 2 seconds. It collects a temperature readingevery 30 minutes for the first 60 days and RH reading every 24 hours.The sensor checks for the presence of light every 15 minutes. If lightis detected once, the sensor clears existing data, and transitions backto the “waiting for pour” state. If no light is detected for 30consecutive days, the sensor stops checking for light.

Advertised Bluetooth Services

The Bluetooth advertisement uses a special format for the broadcast nameof the device: 05-S[12 characters], e.g., 05-Sabcdefghijkl.

This naming format includes the sensor firmware version (“05”) as wellas a delimiter (“S”). The remaining 12 characters are a uniqueidentifier for the sensor based on the MAC address.

Following this format indicates to the smartphone app that: (a) it islikely a Concrete Sensor due to the unique nature of the string format,(b) the version of the protocol to use when communicating with thesensor, and (c) a way of uniquely identifying the sensor from anyothers.

Further, there is a QR code affixed to the front of each sensor. This QRcode encodes the unique 12 character address of the device. This allowsthe smartphone app to correlate an image of the sensor with a BLEadvertisement.

Device Information

A characteristic to print basic information about the sensor, such asthe protocol version.

Data Service

This service is comprised of 7 individual characteristics:

-   1. A readable characteristic reporting the total number of    temperature samples recorded by the sensor.-   2. A writable characteristic, called a “cursor”, indicating how many    samples the smartphone has previously retrieved.-   3. A readable characteristic that transmits all temperature samples    starting with the “cursor” (or 0)-   4-7 are identical to 1-3 but for RH values instead of temperature.-   7. A readable characteristic indicating the number of light-based    resets (explained below).    System Service

A characteristic to read the number of watchdog resets that haveoccurred

A characteristic to force the device to change state

To use this characteristic, a special, secret code is written to forcethe sensor to change state, or to clear all data and reset. This code iskept secret and only intended to be used as part of an onsite diagnosticby a technician.

Process of Connecting a Client to the Sensor Over Bluetooth

-   1. When the client connects, it first reads basic state and    diagnostic information about the sensor, including the light resets    count and the watchdog resets count.-   a. If the light resets count has increased from a previously read    value (starting at 0), the client deletes all previously retrieved    samples.-   2. The client next reads the total number of temperature samples,    then the total number of RH samples. These values are used on the    client side to (a) indicate to the user the progress of data    retrieval, and (b) when to stop polling the sensor for sample data.-   3. The client checks how many previously retrieved temperature and    RH samples it has. It then writes these two numbers to the    corresponding characteristics on the device. For instance, if the    client had previously retrieved 25 temperature samples, it writes    “25” to the temperature cursor characteristic.-   4. The client then polls the sensor for temperature and RH readings.    The sensor starts sending back readings at the cursor+1 and    continues for each successive request until all samples have been    transmitted.-   5. The client disconnects    Process of Retrieving Optical Sensor Readings-   1. Retrieve 3 samples from the phototransistor-   2. Determine variance of each sample using algorithm such as    disclosed in    http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Online_algorithm-   3. Remove the sample with the greatest variance-   4. Average the two remaining values-   5. Check if the result is greater or less than the preset darkness    threshold-   6. Write to the EEPROM a counter indicating how many consecutive    readings of light or dark the sensor has detected.    Process of Collecting Temperature and RH Readings-   1. Turn on power to the sensing chip-   2. Retrieve 3 samples from the sensing chip of either temperature or    RH-   3. Turn off power to the sensing chip-   4. Convert the raw reading from the sensing chip to a value of    either Celsius or a percentage, using the formulae provided by the    sensing chip manufacturer-   5. Determine variance of each sample using algorithm such as    disclosed in    http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Online_algorithm-   6. Remove the sample with the greatest variance-   7. Average the two remaining values-   8. Store the result onto the long term storage system (EEPROM)    Process of Storing Samples

A long term, nonvolatile memory system is available for sample storage(an EEPROM)

The EEPROM is divided up into three logical sections:

-   1. Temperature samples (first 5760 bytes)-   2. RH samples (remaining space on the EEPROM)-   3. Sensor state information (last 14 bytes)

The temperature and RH data are stored as 2 byte hexadecimal integers.The sensing chips report a floating point value of either temperature inCelsius or a percentage (RH). This floating point number is multipliedby 100, rounded off to the nearest integer, and stored. Later, when theclient has retrieved these values, it divides by 100 to find the correct2 decimal place value. These values are stored as two's complement,allowing for negative values (for instance, subzero temperaturereadings).

Smartphone and Sensor Communications Overview

The following describes how the smartphone app communicates with thesensor in accordance with one or more embodiments.

Adding a New Sensor to the Smartphone App

The smartphone app performs a number of functions, one of which is toorganize and communicate with individual sensors. As shown in FIG. 17,there are two ways to add a sensor: (1) A sensor can be added byscanning the QR code affixed to the front of the plastic sensor housing;and (2) A sensor can be added by searching for nearby peripherals.

In the first scenario, a user has removed a new sensor from itspackaging and now wants to add this sensor to the smartphone app. Thesensor turns on automatically when removed from its packaging and beginsbroadcasting a Bluetooth Low Energy advertisement packet (see above).The smartphone app turns on the built-in camera feature, which the userpoints at the QR code to scan.

The QR code is a representation of the sensor's MAC address, whichindicates to the smartphone app what BLE advertisement to look for. Ifit finds a match, the sensor is added to the smartphone app database(and sync′d). If it doesn't find a match after a period of time, italerts the user who is unable to proceed with adding the sensor.

The sensor is periodically broadcasting BLE advertisements except whilethere is an in-progress BLE connection (described in further detailbelow).

BLE Advertisement

Each sensor periodically broadcasts a Bluetooth advertisement packet.These packets are broadcast at approximately 2 second intervals.

The packets are constructed using a format illustrated in FIG. 18.

Version: indicates the sensor firmware running on this particularsensor. It allows the system to make modifications to the protocol thesensor and smartphone app will use to communicate and eliminates theneed to negotiate with a round-trip Bluetooth message when firstconnecting.

Delim: This is a separator from the version number and MAC address. Italso makes it more clear which advertising peripheral is a ConcreteSensors sensor and not some other device, reducing the likelihood ofattempting to connect to some other Bluetooth peripheral that happens tobe broadcasting a similarly formatted packet.

MAC address: Unique identifier, used to separate one sensor fromanother. Factory-determined unique number.

Retrieving Data from a Sensor

As shown in FIG. 19, once a sensor has been added, the smartphone appwill attempt to periodically connect to it to retrieve updated data.

Whenever the app is running, it is listening for BLE advertisements thatmatch the expected broadcast pattern detailed above in BLEAdvertisement. When one of these advertisements is found, the app willcheck:

-   1. that the MAC address matches a previously added sensor in its    database, and-   2. the smartphone app hasn't already connected to the sensor in the    last 30 minutes (this prevents reconnecting to a sensor when there    is no new data to retrieve).

Additionally, the smartphone app will not connect to a sensor if it isalready engaged in synchronizing other data to/from the cloud (toprevent potential collisions with other data).

While a connection is in progress, the sensor stops sending BLEadvertisements. This is a limitation of the Bluetooth implementation andmay change in the future.

FIG. 20 provides additional detail of how the data retrieval processworks (the highlighted section in FIG. 19):

Because the sensor has a limited battery life, it is important tominimize the number of packets sent back and forth and the time it takesto complete a retrieval. To this end, the smartphone app attempts toonly retrieve the data it does not already have. Further, all data isprogressing forward in time: once data has been retrieved, it will neverbe changed and thus should not be re-downloaded.

Two distinct sets of data are collected: temperature and relativehumidity. Both data sets are handled in an identical way, but retrievedin separate operations. This means that the smartphone app connects andfollows the FIG. 20 process first for temperature data, then repeats thesame steps for relative humidity. The process is as follows:

-   1. After connecting to the sensor, the smartphone app first    retrieves the sensor's current light resets count number. See    Handling Light Resets section below for more information.-   2. Next, the smartphone app retrieves the total count of temperature    samples and the total count of RH samples. These numbers are used to    show a progress bar to the user and to calculate the likely date and    time of a sample.-   3. Next, the smartphone app determines what data it has previously    retrieved (either by directly connecting to the sensor, or by    synchronizing with the cloud from someone else who has directly    connected to the sensor). This count is written to the sensor as the    “cursor” and indicates the starting point that new data should be    retrieved from. The temperature count is the first one written.-   4. Finally, the smartphone app continuously requests a new packet of    data until it determines there is no more data to retrieve. It then    either repeats the process for RH data, or disconnects.    Data Packets

An exemplary data packet is illustrated in FIG. 21. Each packet has 20bytes in total, made up of two-byte samples in hexadecimal. Eachtwo-byte sample is divided by 100 to find the decimal equivalent. Twoexamples:

Temperature: 0x9A9→2473→24.73° C.

Relative Humidity: 0x1D1B→7451→74.51%

To determine when data is complete, the sensor pads a buffer with NULL(or returns a buffer with only NULL). For instance, when the smartphoneapp finds a NULL (FIG. 22), it knows there is no more data to retrieveand stops requesting more (if it was temperature, it then moves on torequesting relative humidity data; otherwise it disconnects).

Parsing Data

As shown in FIG. 23, as data is retrieved from the sensor, thesmartphone app begins parsing it. The parsing process takes the datapacket, splits it up into individual two-byte samples and performs theconversion process detailed above to find the decimal equivalent. Inaddition, the smartphone app also determines the date the sample wastaken (detailed below).

While the smartphone app is retrieving data, it is possible for aconnection to be severed and data retrieval to end prematurely. If thishappens, the smartphone app parses and stores the data is had retrievedand attempts to establish a new connection (where it will then write anew cursor to pick up where it left off).

Determining Sample Date and Time

In one or more embodiments, the sensor does not have an onboard clockand has no concept of when a sample was taken. It can only determinerelative times (e.g., 30 minutes from a previous event). As a result,the smartphone app determines the likely time of when a particularsample was taken. The accuracy of this is +/−30 minutes during the first60 days of the sensor operation, and +/−24 hours thereafter, explainedbelow:

If the smartphone app has never connected to a sensor before, and thesensor is still recording temperature data (which occurs every 30minutes during the first 60 days), the smartphone app:

-   1. Retrieves the total count of all temperature and RH data-   2. Takes the current date and time-   3. Subtracts (30 minutes*number of temperature samples taken) from    the current date and time, and sets this result as the time of the    first temperature and RH samples.-   4. Future temperature and RH samples are then determined using this    basis.

In a similar vein, if the smartphone app has never connected to a sensorbefore, and the sensor has completed recording temperature data (butstill recording RH data), the smartphone app:

-   1. Retrieves the total count of all temperature and RH data-   2. Takes the current date and time-   3. Subtracts (24 hours*number of RH samples taken) from the current    date and time, and sets this result as the time of the first    temperature and RH samples.-   4. Future temperature and RH samples are then determined using this    basis.

This has been found to be an acceptable level of accuracy for end users.In an alternate embodiment, a clock may be added to the sensor. This beset by the smartphone app when adding the sensor for the first time.

Handling Light Resets

The sensor has no mechanical switch and instead uses an ambientphototransistor tuned to detect human-visible light wavelengths todetermine interesting events. This phototransistor is constantly beingpolled to determine what state the sensor should be in.

When the sensor is first assembled, it is placed into an interim state(called “ASSEMBLY”). As soon as the sensor is programmed with itsfirmware, it transitions to the “IN_PACKAGE” state. While in this state,the sensor will periodically check for light, indicating it's beenremoved from its packaged and is being installed.

After being taken out of the packaging, the sensor waits for concrete tobe poured around the sensor, encasing it. Whenever light is detected,the sensor all of the temperature and relative humidity data it haspreviously recorded, increments a light resets counter, and proceeds asFIG. 24 details.

When the smartphone app connects to a sensor to retrieve data, itrequests the current light resets count. If this number is greater thanthe light resets count for that sensor the smartphone app had previouslyrecorded, the smartphone app deletes all of its temperature and relativehumidity data and proceeds with retrieving new data from the sensor.

A sensor will never see light while it's encased in concrete, so anytime light is detected in that state, the sensor must not be concrete(and thus it resets the data it had previously collected and startsover). The smartphone knows when data has been reset because of this byvirtue of the light resets counter having increased.

While the exemplary embodiments disclosed herein refer to use of asmartphone in the concrete sensor system, it should be understood thatvarious other computer devices may also be used in the system including,without limitation, personal computers, tablet computers, wearablecomputers (e.g., smart watches and smart glasses), personal digitalassistants, and generally any computer device capable of communicatingwirelessly with the sensor devices. The computer devices includeoperating systems (e.g., Android, Apple iOS, and Windows Phone OS, amongothers) on which applications run. The operating systems allowprogrammers to create applications or apps to provide particularfunctionality to the devices. A representative computer device includesat least one computer processor and a storage medium readable by theprocessor for storing applications and data. The computer device alsoincludes input/output devices including a display for visual output,e.g., an LCD or LED display, which may have touch screen inputcapabilities.

Having thus described several illustrative embodiments, it is to beappreciated that various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to form a part of thisdisclosure, and are intended to be within the spirit and scope of thisdisclosure. While some examples presented herein involve specificcombinations of functions or structural elements, it should beunderstood that those functions and elements may be combined in otherways according to the present disclosure to accomplish the same ordifferent objectives. In particular, acts, elements, and featuresdiscussed in connection with one embodiment are not intended to beexcluded from similar or other roles in other embodiments. Additionally,elements and components described herein may be further divided intoadditional components or joined together to form fewer components forperforming the same functions. Accordingly, the foregoing descriptionand attached drawings are by way of example only, and are not intendedto be limiting.

The invention claimed is:
 1. A sensor device for monitoring propertiesof a building material within which the sensor device can be embedded,the sensor device being packaged in a removable light blockingpackaging, the sensor device comprising: a controller; memory associatedwith the controller; one or more sensors connected to the controller formeasuring one or more properties of the building material; an opticalsensor connected to the controller for detecting the presence of light;a power supply for powering components of the sensor device; and acommunication module connected to the controller; wherein the controlleris configured to receive a signal from the optical sensor when light isdetected after the sensor device is removed from the light blockingpackaging, and to responsively activate the sensor device, and whereinthe controller is configured to receive data on the one or moreproperties of the building material from the one or more sensors afterthe sensor device is removed from the light blocking packaging andembedded in the building material, and to wirelessly transmit data onthe one or more properties of the building material to an electronicdevice external to the building material through the communicationmodule.
 2. The sensor device of claim 1, wherein the building materialcomprises concrete, asphalt, or epoxy.
 3. The sensor device of claim 1,wherein the one or more properties comprise building materialtemperature, vibration, pH, gas and particle presence, load, acousticproperties, and relative humidity.
 4. The sensor device of claim 1,wherein the electronic device comprises a smartphone or a personalcomputer.
 5. The sensor device of claim 1, wherein the sensor devicecommunicates with the electronic device using Bluetooth, Bluetooth LowEnergy, ANT, IEEE 802.11 and WiFi, RFID, NFC, Thread, LoRa, or ZigBee.6. The sensor device of claim 1, further comprising an outer housingcontaining at least the controller, the memory, the power supply, andthe communication module, wherein the sensor device further comprises acable tie connected to the outer housing attachable to a structurewithin the building material.
 7. The sensor device of claim 1, furthercomprising a machine-readable code on an outer housing of the sensordevice uniquely identifying the sensor device.
 8. The sensor device ofclaim 1, wherein the power supply comprises a battery and a powerregulator.
 9. The sensor device of claim 1, further comprising an outerhousing including a portion permitting light to pass through to theoptical sensor within the housing.
 10. The sensor device of claim 1,further comprising an outer housing having an opening covered by amembrane filter, said membrane filter enabling moist vapor to enter theouter housing for sensing by the one or more sensors, while inhibitingor preventing liquid, chemicals, or debris from entering the outerhousing.
 11. The sensor device of claim 10, wherein the membrane filtercomprises a PTFE membrane.
 12. The sensor device of claim 1, wherein thedata transmitted by the sensor device is encrypted, and the electronicdevice is configured to decrypt the data.
 13. The sensor device of claim1, wherein to responsively activate the sensor device comprises toresponsively place the sensor device in a waiting-for-pour state whenthe optical sensor detects light when the light blocking packaging isremoved, and then to place the sensor device in an encased state whenthe optical sensor subsequently detects an absence of light when thesensor device is embedded in the building structure.